The present invention relates to vehicle control systems and more particularly relates to a method and a device for controlling the longitudinal dynamics of a vehicle.
The present invention relates to the driving dynamics control systems of an automotive vehicle and, therefore, the disclosure of applicant""s application No. 196 54 769.5 of Dec. 28, 1996 is included in its full contents because this application also refers to the longitudinal dynamics control of vehicles.
Modern processes and devices for controlling the longitudinal dynamics of a vehicle comprise an engine which is controlled by engine management or a corresponding device, a controlled brake, a controlled transmission as well as a complex vehicle dynamics control which predetermines nominal values for the brake, the transmission and the engine in response to the driver""s demands and internal and external operating conditions of the vehicle.
Modern engine management often detects the nominal engine torque as an input quantity, and the brake can be supplied with the nominal brake pressure as an input quantity. These nominal values are generated by an ICC control (Intelligent Cruise Control) to which, in turn, the above-mentioned quantities are sent. Among these are the driver""s speed demand, which is imparted to the vehicle via the accelerator pedal and brake pedal, various quantities sensed by sensors such as speed, longitudinal and transverse acceleration, distance from and relative speed with respect to a vehicle which drives ahead, etc. In longitudinal dynamics control operations, various components influence the nominal engine torque or the nominal brake pressure: On the one hand, the mentioned nominal values are determined according to a predetermined nominal acceleration (which, in turn, results from different components, for example, requirements indicated by the driver, cornering speed control, automatic cruise control, etc.). In addition, there is the traction slip control system TCS by which spinning of the wheels is prevented. TCS control operations reduce the torque requirements to be met by the engine. Engine stall torque control MSR prevents locking of the wheels when shifting down, for example, when shifting from the third into the second gear on a slippery road surface and with rear-wheel drive. Engine stall torque control increases the torque requirements. An automatic stability management system ASMS intervenes especially in the braking of the individual wheels, but can also take effect on the transmission and the engine. For example, individual wheels may be optionally braked with an ASMS control, also known as driving stability control system, in order to prevent a vehicle from skidding.
The above-mentioned components thus take effect on the determination of nominal values for the engine, transmission and/or brake. Up to now, however, no satisfying solution has been found regarding the joint processing of all influencing variables to produce nominal values.
An object of the present invention is to provide a process and a device for controlling the longitudinal dynamics of a vehicle wherein the specification of nominal values for the engine and/or the brake is achieved easily and in conformity with the individual driving situations.